865638049 has 2 divisors, whose sum is σ = 865638050. Its totient is φ = 865638048.

The previous prime is 865638047. The next prime is 865638061. The reversal of 865638049 is 940836568.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 447026449 + 418611600 = 21143^2 + 20460^2 .

It is a cyclic number.

It is not a de Polignac number, because 865638049 - 2¹ = 865638047 is a prime.

Together with 865638047, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 865637993 and 865638011.

It is not a weakly prime, because it can be changed into another prime (865638047) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 432819024 + 432819025.

It is an arithmetic number, because the mean of its divisors is an integer number (432819025).

Almost surely, 2^865638049 is an apocalyptic number.

It is an amenable number.

865638049 is a deficient number, since it is larger than the sum of its proper divisors (1).

865638049 is an equidigital number, since it uses as much as digits as its factorization.

865638049 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1244160, while the sum is 49.

The square root of 865638049 is about 29421.7274985681. The cubic root of 865638049 is about 953.0421587683.

The spelling of 865638049 in words is "eight hundred sixty-five million, six hundred thirty-eight thousand, forty-nine".